1. Technical Field
The present invention relates to a novel process for producing a cooked food analog from soybeans, and to the food analog produced thereby. The present invention is particularly applicable to the preparation of a cooked animal protein analog, such as a ground meat analog or a scrambled egg analog.
2. Description of the Prior Art
The production of tofu consists of two main steps; first, the preparation of soymilk; and, second, the coagulation of the soymilk to form curds which are then pressed to form tofu cakes.
U.S. Pat. No. 4,579,749 discloses a process for producing a ground meat analog from tofu. The process comprises the steps of extracting soymilk from soybeans, coagulating the soymilk to form curds and then pressing the curds to form tofu cakes. The tofu cakes have a solids content in the range of about 35%-50%. The tofu cakes are then shaped into a form like ground meat, for instance in a meat chopper, and heat treated, for instance in a steamer at 100.degree. C. for 10-20 minutes. The patent indicates that the heat treated product has a hardness and chewiness similar to the hardness and chewiness of ground meat. The patent states, in column 3, lines 55, 56, that the "food produced by the method of the invention is fundamentally a pressed tofu".
U.S. Pat. No. 4,645,681 discloses a process for preparing tofu which comprises obtaining soybean milk, or an aqueous solution of isolated soybean protein, coagulating the milk to form curds, adding additional soybean milk to the curds, crushing the curds while in the presence of the soybean milk, adding additional coagulant to the crushed mixture of curds and soybean milk, and heating the same to further coagulate the mixture. The heating is carried out at about 85.degree. C. for about 40 minutes in a heat-resistant plastic container which is sealed. The product obtained is described as having good texture and taste. The purpose of the process is to mechanize the traditional tofu making process by eliminating labor intensive and imprecise steps. The end product is intended to be as similar as possible to traditional tofu. There is no cooking of curds.
U.S. Pat. No. 4,636,398 discloses a process for making retort packed tofu which comprises soaking soybeans in water and leaching the soluble saccharides from the soybeans, grinding the soybeans in water to form a slurry, and then filtering the slurry to obtain soybean milk. The soybean milk is adjusted to a pH of about 4.5 precipitating protein which is separated from the milk, for instance by centrifuging. The milk is admixed with a coagulant, such as delta-glucone lactone, and introduced into a retort in which it is sealed and heated to effect both sterilization and coagulation. This provides a retort packed tofu. As in U.S. Pat. No. 4,645,681, the patent describes a process for mechanizing the traditional tofu making process. There is no cooking of the curds.
U.S. Pat. No. 4,789,556 discloses a process similar to that of U.S. Pat. No. 4,636,398. A soybean protein isolate, having a coagulation ability of at least 80, is added to soybean juice (soymilk). The soybean juice is then homogenized and sterilized. A coagulant is added to the soybean juice to form a mixture. This mixture is introduced into a container which is sealed and heated to obtain a packaged, aseptic curd having a firmness of at least 130, as measured by a curd tension meter. This process produces what can best be described as a "hard kinugoshi" tofu. The curds are not separated from the whey. There is no formation of distinct curds and no cooking of curds.
U.S. Pat. No. 4,511,588 discloses a process in which a coagulant is added to soybean milk. The pH of the soybean milk is adjusted to 6.5-7.5, and the soybean milk is then poured into heated oil at 75.degree.-140.degree. C. This produces a granular product having a surface coated with an oily film.